Insulin-dependent diabetes mellitus (IDDM) is characterized by destruction of the insulin-producing pancreatic beta-cell. Allogeneic islet transplantation has the potential to effectively treat and possibly cure diabetes it successful. However, several factors effect the success of islet transplantation including the large number of islets need for transplantation, the viability of the transplanted islets, and regulation of the allo and autoimmune responses to the transplanted cells. One approach to facilitate islet transplantation is through the genetic modification of islets to express anti-apoptotic or immunoregulatory agents. We have been examining the ability to modify murine and human islets by gene transfer with different viral vectors including adenovirus, lentiviruses, different serotypes of AAV, HSV and non-viral vectors in order to identify the appropriate vector for clinical application. We also have examined the ability to inhibit IL-1beta mediated islet dysfunction and Fas mediated apoptosis in culture through gene transfer of IL-1 inhibitors and anti-apoptotic genes. However, our preliminary results suggest that the most effective method for protection of islets in culture is mediated by adenoviral gene transfer of IkB, an inhibitor of NF-kB. Inhibition of NF-kB activity in murine and human islets in culture completely blocked IL-1beta mediated beta cell dysfunction, induction of NO production and Fas-mediated apoptosis. Thus NF-kB inhibition, unlike other anti-apoptotic agents, is able to prevent both islet dysfunction and apoptosis. In addition, we have been developing approaches to deliver therapeutic proteins to islets using cationic peptide transduction domains. We have demonstrated that peptide-mediated transduction of an NF-kB inhibitor is also able to block beta cell dysfunction in culture and during islet isolation. Thus the focus of this proposal is to evaluate further the use of NF-kB inhibitors, delivered by peptide mediated protein transduction and by gene transfer, to improve the viability of islets in culture and to improve their survival following transplantation into both syngeneic and allogeneic murine recipients. Two different types of NF-kB inhibitors will be evaluated, IkB that blocks both basal and cytokine stimulated NF-kB activity and inhibitors of the IkB kinase, IKK, that prevent phosphorylation of IkB and subsequent ubiquitin mediated degradation. The successful completion of the proposed studies should determine if NF-kB inhibition in islets by peptide and gene mediated transduction is able to improve islet viability prior to and post-transplantation.